Automatic program selector for radio receivers



NOV. 10, 1936. w; ALLEN, JR 2,060,546

AUTOMATIC PROGRAM SELECTOR FOR RADIO RECEIVERS Filed 'April 29, 1955 I 2Sheets-Sheet 1 c FIGIZT /b v 56 /'3'I I INVEN TOR M .1.@11-.. yr.

Nov. 10,1936. w A L JR 2,060,546

AUTOMATIC PROGRAM SELECTOR FOR RADIO RECEIVERS Filed April 29, 1935 2Sheets-Sheet 2 FIRE I6 I 31 l:

l6 b ns-i ise IN VEN TOR am; w. w i

Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE Edward W. Allen, Jr.,Washington, D. C.

Application April 29,

18 Claims.

This invention relates to automatic tuning devices for radio receivers.

Heretofore in the art, automatic control devices which are adapted toreset the tuners of radio receivers at given intervals have employed aclock or timing mechanism to determine the time at which the tuner is tobe reset and which controls a motor or source of power which performsthe work of resetting the tuner. In the ma- 10 jority of these devices,the clock closes electrical contacts which control an electric motor andcauses it to set the tuner to the desired position. It has been foundthat such contacts, exposed to grease and dirt over a long period oftime, are

conducive to false operation of the device.

In order to assure positive operation of such devices it has been founddesirable to employ mechanical means for performing the desiredfunctions wherever possible.

It has been known heretofore to control the automatic selection of radioprograms by automatic mechanical means, but in all such devices of whichI am aware, it has been necessary in setting up each sequence ofprograms to make individual adjustments of the stops which determine thetuning of the set. When such adjustments are necessary, a great deal ofcare must be exercised in order to assure the proper tuning, and where along series of programs is desired such a procedure may be exceedinglytedious. In some devices of this nature it is even necessary to tune theset to each station to make the adjustment. In the invention hereindescribed, such a procedure is not necessary.

In the majority of localities, owing to our present system ofbroadcasting networks, any desired sequence of programs may usually beobtained by the proper sequential selection of programs from a few, saythree or four, broadcasting stations. In the herein described invention,a plurality of stops, equal in number to the broadcasting stationsusually selected, are provided. By tuning the radio set to thesestations in turn, the stops may be adjusted to control thereafter thetuning of the set. So long as these same stations are selected in futureprograms, regardless of the sequence in which selected, these stops willnot be again adjusted. In many cases, they may be adjusted by the dealeror servicing agency in accordance with the wishes of the owner upon thepurchase of the set and never be changed thereafter.

For the purpose of setting up any given sequence from the programsbroadcast by the selected stations, a series of selector elements is.

1935, Serial No. 18,956

provided each of which is manually adjustable to positions one greaterin number than the stops. The adjustment of an element to one of thepositions prevents any of the stops from acting and corresponds to a noprogram or off position. The adjustment of the element to any otherposition causes the corresponding stop to control the tuning of the set.It is thus apparent that by making the selection of a station dependentupon the adjustment of the element to one of, say, four positions, eachof which may be quickly and easily selected, instead of to any one of ahundred or more positions which must be adjusted with care, much of thetedium of setting up the program series is relieved. Further means areprovided for rotating the tuning device at intervals corresponding toconventional broadcast periods and for controlling the stops to restrainthe tuning device at desired stations in accordance with the adjustmentof each of the series of selector elements. For the purpose ofdisclosing this invention, a period of 15 minutes has been chosen as thebroadcast period.

In order to prevent discomfort upon the part of the audience, it isdesirable that the set be prevented from responding to signals duringthe tuning period, and also that all stations be received at the samevolume level. Some radio sets are equipped with automatic volume controlto perform this function but this has not proven to be entirelysatisfactory, particularly where broadcasting stations of widely varyingpower are concerned. For this reason it has been found desirable toprovide herein a mechanically operated volume control which may beseparately adjusted for each station, and which has the additionalfunction of silencing the set during the tuning operation.

Accordingly, it is an object of this invention to produce a device whichwill automatically reset the tuner of a radio receiver to positionscorre sponding to desired stations at given intervals and in accordancewith a predetermined sequence.

Another object is to produce a device which will silence the radio setduring the tuning operation.

Another object is the production of a device which will automaticallyadjust the volume of signal reception to a uniform level regardless ofthe power of the transmitting station simultaneously with the tuningaction, and which is also manually adjustable to vary this level ofreception.

Another object is to produce a device which will turn on the radio setat a desired future time, tune it to various stations in any desiredsequence, and turn off the set at the end of the sequence.

Another object is to perform the above functions by mechanical meanswherever feasible.

Another object is to supply the mechanical energy necessary to performthe above functions from a single continuously rotating motor of smallsize.

My invention will be more clearly understood when explained withreference to the drawings, of which:

Figure I is a side view of one form of the device.

Figure II is a broken front view of the same form of the device.

Figure III is a top view of the timing and driving mechanism.

Figure IV is a detailed view of the adjustable stops and separatingwashers of the stop assembly of Figure I.

Figure V is a detailed view of one of the rotatable selector buttons ofFigure I.

Figure VI is a schematic diagram of the electrical connections of thesignal silencer and level control of the first modification.

Figure VII is a side view of another form of the device.

Figure VIII is a front view of a manually adjustable selector bar ofFigure VII.

Figure IX is a broken front view of the second form of the device.

Figure X is a detailed view of the tip of the selector arm of the secondform of device.

Figure XI is an expanded view of a part of the timing and drivingmechanism.

Figure XII is a rear view of the assembly for supporting and rotatingthe selector arm of the second form of device.

Figure XIII is an enlarged side view of the selector element of FigureVIII.

Figure XIV is an enlarged front view of the same element.

Figure XV is a circuit diagram showing the cooperation of the automaticand manual volume control means.

First modificationP-Structure.Referring to Figures I to VI and XI of thedrawings in detail, a variable condenser or condenser gang I, whosefunction is to tune the radio receiver, has a rotary shaft 2 carryingrotor plates in the conventional manner. This condenser is of the 180type and may conveniently have several degrees of movement beyond itspositions of maximum and of minimum capacity. A flat spiral spring 3 isattached at its inner end to the shaft 2 and its outer end attached tothe condenser stator at 4, and tends to rotate the rotor to its extremeclockwise position. A setscrew 5, in the hub of gear 6, secures thelatter against rotation on shaft 2. Gear 6 carries a pawl I, pivoted at8, and urged against the rear surface of flat spring member I9 by thespring 9. Gear 6 also carries a pin I which opens the power supplyswitch 60 when the rotor assumes its most clockwise position. Switch 6|!is shown as a simple set of spring supported contacts but may be of anyconventional type which is suitable for controlling the power supply ofthe radio set. A pinion II, carried by a rotatable shaft l2, meshes withgear I5. Shaft I2 carries a pair of governor springs I3 havingflyweights I4. When in rotation, springs I3 bear inside of a metalliccup I5 connected to the set antenna as shown in Figure VI. When at rest,one of the springs, which is longer than the other, makes contact withthe annular resistor III. This resistor, which may be of the order of50,000 ohms, is connected at one end to the cup and at the other end toground, and the position of spring I3 thereon determines the signalinput to the radio set.

A bushing 20, rotatably mounted on shaft 2, is prevented from turningtherewith by a flat spring member I9 which is secured at its center tothe rear or disc portion of bushing and is supported at its ends bystandoff bushings from panel 30. The bushing carries a bossed washer 26which serves as a spacer and bearing for the eye portion of the selectorarm 2| which is freely rotatable thereupon. Washer 26 is prevented fromrotating upon bushing 20 by tits, similar to those shown at 28 in FigureIV, which engage two grooves in the side of bushing 20. Bushing 20 alsocarries a plurality of rotatable washers 22, separated by washers 23having tits 28 to prevent rotation. The rotatable washers 22 haveforwardly projecting stops which extend, in a clockwise direction,gradually increasing distances into the path of pointer 29 attached tothe end of shaft 2. The pointer 29 has the double function of indicatingthe condenser setting and acting as a stop to determine this settingunder automatic operation. Threaded upon the forward end of bushing 20is a clamping nut 24 which may be tightened sufficiently to hold washers22 in any position to which they may have been set. The whole assemblycarried by bushing 20 is urged rearwardly under the influence of flatspring I9.

In order to position the assembly in various axial positions and thusdetermine which of the stops 25 intercepts the pointer 29, panel 30 hasa circular array of 48 rotatable buttons 3|. These buttons are dividedinto sectors w, b, c, (1, having graduated heights and separated bywalls e. The buttons may be turned so that any sector will be presentedto the tip of the selector arm H and when it rests thereon willdetermine the axial position of the stop assembly. The walls e whichseparate the sectors a, b, c, d, serve to lock the selector arm againstrotation until it is moved forwardly in an axial direction. Springwashers 32 normally hold the buttons against the panel but allowsufficient forward motion so that the ridge on the rear of the button 3|will ride from one groove in the panel 30 to the other as the button isrotated. The ridge and its cooperating grooves insure correctorientation of the button as Well as a permanent setting until manuallyrotated.

To provide for rotation of the selector arm 2| to successive ones of thebuttons, a slot 21 in spring I9 and the disc portion of bushing 20allows the pawl I to engage an annular set of ratchet teeth in the eyeportion of selector arm 2|. The inclination of pawl I causes theassembly to move forward as the gear 6 approaches its extremecounterclockwise position, until the tip of the arm 2I overrides thewall e of the button upon which it has been resting. The selector arm isthen rotated counterclockwise by the pawl until the pawl strikes the endof the slot 21. At this time the arm has rotated until its tip is overthe next button. As the gear 5 begins its clockwise motion ashereinafter ex plained, the tip of arm 2| is dropped into the presentedsector of this button.

A synchronous motor 33 drives the gear 34 at one revolution each fifteenminutes. Gear 34 drives shaft 35 to which is attached the inner is onthe surface of greater radius.

end of flat spiral spring 36. The outer end of spring 36 is attached tothe cross member of the U-shaped rider 31. Rider 3! turns freely and hasa limited axial movement on shaft 35. A detent 38,'when down, restrainsthe rider against rotation.' If the detent is lifted, the cam surfaceI31 of the rider (Figure XI) engages the rear surface of the cam 54 andthe rider rotates uniformly with the gear 34. Detent 38 is fixed to theforward end of a rotatable shaft 39 to the rear end of which is fixed anL shaped mem ber comprising the arm 40, terminating in a cam surfacewhich cooperates with pinion 55, and the arm 5|, terminating in a camfollower, which cooperates with the cam 50. Loosely pivoted upon shaft39- is an inverted U-shaped member 4! having a downwardly extending arm42 which terminatesin a cam surface extending into the path of rotationof rider 3?, and a second downwardly extending portion which iscounterweighted to urge the member in a clockwise direction of rotationand upon which is pivoted the pawl 43. Pawl 44 is loosely pivoted uponshaft 39, and a stop 53 punched from member 4| bears upon its upper sideto prevent arm 42 from moving too far into the path of rider 31. Hub 45is freely rotatable on shaft 35 and carries a gear 46 which meshes withgear 3. Gear 46 has a forwardly extending stop 41 which will clear thecrossmember of rider 31 when the latter is restrained by the detent 38or by the underside of the cam 54. Figure XI is an expanded view ofthese elements, the operation of which will be explained in detailhereinafter.

A shaft 48 carries a ratchet wheel 49 to the rear side of which is fixeda cam 55 having two circularsurfaces each subtending approximately 180upon which rides the follower 5|. The approach to the surface of greaterradius is in the form of a steep ramp so that the follower 5| will ridethereover during the rotation of ratchet wheel 49 through an anglesubtended by one or two teeth. If two teeth are required, the detentshould not clear rider 31 until the follower 5| The approach to thesurface of lesser radius is radial and allows the follower 5! to drop tothis surface immediately. Shaft 48 also carries a pointer 52 whichpass-es over an index on the panel. If the panel carries 48 of thebuttons 3|, or sufficient to set up programs for twelve hours, theratchet wheel 49 should have 96 teeth and the index should be dividedinto two twelve hour periods, one marked Off. when the cam follower 5|is upon the surface of greater radius, and the other marked Oh, when thefollower is upon the surface of lesser radius.

To provide for 'manual selection of radio programs, a shaft 55,rotatable and axially movable in split bushing 5l, carries a pinion 56which is adapted to mesh with gear 46. Moving the pinion rearwardly tomesh it with gear 46 causes it to engage the cam surface of lever 40 andraise the detent 38.

The device as shown is capable of selecting programs from threedifferent stations in any desired sequence at 15 minute intervals over aperiod of twelve hours. If desired, for convenience in setting up thesequence, the panel 30, carrying the buttons 3|, may be indexed as aclock face, the buttons being located at 15 minute intervals. It will beapparent from the foregoing description that the selector arm is rotatedin a counterclockwise direction and the index would have to be arrangedcounterclockwise. It

would be commercially desirable to have the index in the conventionalform, and this may be done by constructing the device as a mirror imageof this disclosed in detail herein.

Operati0n.--To adjust the device, the pinion 56 is forced rearwardlyinto engagement with the gear 46. Split bushing 51 has sufficientfriction to hold the condenser in any desired position against thetension of spring 3. The condenser is manually rotated to its extremecounterclockwise position. This allows switch 50 to close and turn onthe radio set. Clamping nut 24 is loosened until washers 22, carryingstops 25, are manually rotatable but still have sufiicient friction toremain in any selected position. The stops 25 are manually rotatedcounterclockwise until the three are bunched against the pointer 29,which will then lie in a horizontal position. The button 3| lyingbeneath the selector arm 2|, which is then thrust forward with the stopassembly by pawl I, should be rotated so that sector a is presented tothe tip of the selector arm. The condenser is then rotated clockwiseuntil the most counterclockwise of the desired stations is reached andthe volume set at the desired level. It will be noted that as thecondenser is rotated, the spring contact l3 will rotate around theresistor i8, causing the input from the antenna to be varied inrecurrent waves. It is imperative therefore that the gear ratio betweenthe gear 6 and the pinion ll be sufficiently high to cause an input peakto occur at each kilocycles around the dial, so that each station willreceive a peak. Since a slight movement of the condenser is necessary toeffect the desired volume adjustment, the set should have fairly broadtuning characteristics or be designed with a signal seeking circuit suchas that disclosed in Radio Retailing for March 1935 at pages 39 and 40,in order that the quality of reproduction be not impaired. Rotation ofthe condenser to the station causes the bunched stops 25 to be rotatedby pointer 29, the first stop resting against the side of the pointer.Next, the button 3| lying next in a counterclockwise direction isrotated manually until sector b is presented to the selector arm tip.The condenser is again rotated to its extreme counterclockwise position,which causes selector arm 2| to be rotated to the second button. lowingthe arm to rest on sector I) of this button. Sector I) being lower thansector a, the stop assembly, under the influence of spring |9, assumes amore rearwardly position than before. The pointer 29 passes over thefirst or shortest of the bunched stops. 25 and engages the second,carrying it and the third stop to a position corresponding to thefrequency and volume of the second of the desired stations. The nextcounterclockwise button is then rotated to present sector 0 and thesteps repeated to position the third stop at the desired position. Thecondenser is then rotated to the extreme counterclockwise position toforce the assembly outward and the clamping nut 24 tightened to clampthe stops in a fixed position. Flat spring I 9 is designed to holdbushing 20 stationary while nut 24 is being tightened.

If the button beneath the selector arm is turned to present sector d,the stop assembly assumes its most rearward position and when thecondenser is rotated in a clockwise direction the pointer 29 will passfreely over all the stops 25, and the condenser may be turned manuallyin the conventional manner. Since rotating the The condenser is rotatedclockwise, al-

condenser to one extreme position will step the selector arm off theproperly adjusted button, and rotating it to the other will turn off theradio set, each of these positions should be beyond the normal tuningrange of the condenser or the circuit design be such that the wholebroadcast band will lie within these positions.

To condition the receiver for selecting a sequence of programs, thebuttons 3| are manually rotated to present sectors o b, or c in thedesired order in a counterclockwise direction around the face of thedial. The button immediately preceding the sequence is rotated topresent sector (1 and. the selector arm placed thereon. Pinion 56 ispulled forward and disengaged from gear 46, allowing the condenser torotate to the extreme clockwise position, cutting off the set. Lever 40drops and allows detent 38 to fall into the path of rider 31 if thepointer 52 indicates On. If Off is indicated, cam follower preventsdetent 38 and lever 40 from dropping.

A small synchronous motor 33 drives gear 34 continuously and, if detent30 is lifted, the rider 31 moves therewith. Each time that the riderengages the cam surface of the arm 42, it rocks the member 4| about theshaft 39 and causes pawl 43 to step ratchet wheel 49 one tooth. Thisoperation continues, one tooth each 15 minutes, until cam follower 5|drops down to the smaller radius cam. This allows detent 30 to drop intothe path of rider 31. On its next revolution, gear 34 will tensionspring 36 since rider 31 is restrained. When gear 34 has made nearly acomplete revolution, the outer surface of cam 54 carried thereby engagesthe near leg of rider 31 and forces it to the rear until the riderescapes the detent 38. When the condenser is in the extreme clockwiseposition, the stop 41 on gear 46 is directly opposite the rider and willbe engaged thereby when the rider is forced to the rear. As soon as therider is released from the detent, urged by the spring 36 it willovercome spring 3 and rotate the condenser to the extremecounterclockwise position, stepping ratchet wheel 49 as it passes thearm 42, and stepping the selector arm to the first button of the seriesas it reaches this position. At this position, the cam surface I31 ofthe rider engages the inner surface of the cam 54, moving the riderforward and freeing it from stop 41. Selector arm 2| drops to thepresented sector of the first button as the condenser slowly rotatesclockwise under the control of the governor, due to the action of spring3, and the corresponding stop intercepts the pointer 29. During rotationof the condenser, the governor springs I3 contact the cup I5 andshort-circuit the antenna circuit, silencing the set. When pointer 29engages the selected stop 25, the longer spring contacts the annularresistor l8 at the point selected for this station, and causes thesignals to assume the proper level.

At the end of the next 15 minute period the operation is repeated, thestop 41 on gear 46 not being opposite the detained rider 31 but at apoint in its path of travel corresponding to the position of the firststation. To assure that the rider, when released under these conditions,will travel close to the gear 46 and contact stop 41, the spring 36 issecured to the shaft 35 and the rider 31 so as to tend to move the ridertoward gear 46. To prevent impact of the rider with the stop 41. thespring is made self governing by winding it in a tight spiral, as shownin Figure II, and filling it with a light grease. The dial index forpointer 52 indicates the length of time before the set will begin orcease operation. So long as the pointer is upon the on" side and themanual tuning knob is pulled outward, the set will hunt for a newstation each 15 minutes. If the button selected by the arm 2| presentssector 01, the condenser will resume its extreme clockwise positionafter the hunting action and the set be turned off by the opening ofswitch 60. Pointer 52 is manually rotatable in a clockwise direction sothat operation can be initiated or terminated at any time up to twelvehours later.

Second modification--Structure.-Referring to Figures VII to X, XII,XIII, and XIV of the drawings in detail, the condenser shaft 2, which isspring biased in a clockwise direction by a spring 3 as shown in FigureI, has fixed thereto a bushing I20. The bushing has fixed thereto a gearI06 and is grooved upon its upper and lower sides to accommodate thetits 20 of washers 23. Interposed between washers 23 are adjustable stopm mbers I22 having forwardly projecting stops I25. A clamp nut I24 isthreaded on bushing I20 so as to clamp the stop assembly against theshoulder of the bushing. The central openings of members I22 are oval sothat they may be adjusted radially as well as circumferentially and thelower ends thereof are in the form of curved legs terminating in camsurfaces I65. A light spring I63, fastened at one end to the shoulder ofbushing I20, has a forwardly disposed portion which engages the legs ofthe members I22 and, when they are released by loosening the clampingnut I24, collects them against the pin I64 which projects from gear I06.Owing to the curved form of the legs, the members are collected in sucha manner that the tops of the oval openings lie against the bushing I20.Gear I06 meshes with a pinion I69 which in turn meshes with a gear I10driving the governor |1I for controlling the speed of rotation of thecondenser. Pinion I69 rotates upon a stub shaft carried by lever I14which is pivoted upon a shaft I12, upon which the gear I10 is freelyrotatable. Lever I14 also carries a shielding cylinder I13 formed ofmaterial of good electrical conductivity and which is insertable betweenthe primary I60 and the secondary I59 of the antenna coupler. Upon theother end of the lever I14 are cam followers I66 and I61. A manuallyrotatable male and female spiral cam I60 cooperates with the followerI61. The spiral is open so that the follower may cooperate with eitherthe male or the female surface of the cam. Follower I66 cooperates withcam surfaces I65 and will oscillate the lever in accordance with theradial adjustment of the members I22.

Meshing with gear I06 is a gear train I6| with which the manual controlpinion 56 is caused to mesh for manual operation as in the firstmodification.

Rotatably mounted upon the clamping nut I24 is the selector arm |2|having a hub which terminates at the rear in a disc portion having 96annular ratchet teeth, equal in number to the adjustable stationselector bars I3I, which are, in this modification, sufficient fortwenty-four hours of continuous operation. The tip of the selector armhas a pair of cam surfaces upon its under side which straddle theselector bars when the tip of the arm is allowed to rest upon the bars.See Figure X. The selector bars, shown enlarged in Figures XIII and XIV,slide radially in slots I32 in the panel I30. The panel I30 has a seriesof annular grooves I33 in the rear thereof with which the spring detents43I on bars I3I cooperate to maintain the bars in any of the fourpositions selected. Ears 23I and 33I serve to maintain the bars normalto the panel so that they will slide without binding. By sliding thebars inwardly or outwardly, any one of the steps a, b, c, (1 may be madeto cooperate with the tip of the arm I2I.

Spring member I I9 has an eye which fits over the hub of selector arm I2I, and bears against the disc portion thereof, tending to move theselector arm toward the panel. The ends of the spring II9 are supportedfrom stand-off bushings carried by the panel I30. Spring member II9 alsohas a stop I62 adapted to coact with the stops I25, and a guide slot I21for pawl I43. Notch 243 of pawl I43 rides on guide I21 which has arearwardly bent portion which prevents the pawl from engaging more thanone tooth of the ratchet I26 for each reciprocation, regardless of thelength of the stroke. Pawl I43 is inclined, similar to pawl 1, and thelength of the stroke will vary, depending upon the position of theassembly comprising the spring and its associated elements. Pawl I43 isactuated by lever I42 whose lower end lies in the path of the rider 31.A bellcrank I5i, pivoted upon the panel I36, bears against the front ofspring H9 and beneath lever 40, which controls detent 38, and lifts thedetent when the selector arm I2I rests upon the top step (d') of theselector bars I3I. Counterweight I4I for lever 40 is provided so that aslight pressure of bellcrank I5I is sufficient to raise lever 40.

The spring tensioning and releasing elements 33 to 31, 45, 46, and 41are not shown in detail in these figures since they are the same as inthe first modification. The gear 46, in this instance, drives thecondenser gear I06 through the medium of pinion I69 and gear I10.Condenser gear I06 has a pin I0, not shown, to control a switch 60 forthe power supply as in the first modification. Pin I64 may be made toperform this function by locating the switch lever close to the gearI06, so as not to interfere with the operation of stop members I22.

Operation.-The cam I68 is rotated to its extreme counterclockwiseposition, causing the female surface to engage the follower I61 and torock the lever I14 about the pivot I12. This removes the follower fromthe paths of the cam surfaces I65 of members I 22 and causes theshielding cylinder I13 to be moved upwardly between the primary andsecondary of the antenna coupler. The selector arm I2I is manuallypulled forward and set upon step .d' of a selector bar I3I Clamping nutI24, which has a left handed thread, is loosened until a click is heard,denoting that the spring I63 has collected the members I22 against thepin I64. With the manual control pinion 56 disengaged, clamping nut I24is then tightened until the condenser tends to turn therewith againstthe tension of the spring 3. This insures proper tension to enablesetting the members I22 without being moved thereafter by the springI63. Manual control pinion 56 is next engaged with the train I6I and thecondenser rotated to the extreme counterclockwise position. Threeselector bars I 3I are then positioned so that the tip of the selectorarm I 2I will rest upon steps 0, b, and a, respectively. Arm I2I ismanually placed upon step c of the first bar and the condenser rotatedto the most clockwise of the three stations desired to be selected. Thelongest of the stops I25 will engage the stop I62 and be positionedcircumferentially. By rotating the cam I68 clockwise, follower I61 willbe moved upward and will cause follower I66 to move member I22 upward,and at the same time will cause the shielding cylinder I13 to bewithdrawn from between the primary and secondary of the antenna coupler,increasing the volume of reception. In addition to its shielding efiect,the cylinder I13 has a varying energy absorbing effect, due to itsvariable coupling with the primary I60 and the secondary I59, whichenhances its volume controlling characteristics. When the volume hasbeen adjusted to the desired level, the cam I68 is turned to the extremecounterclockwise position, and the condenser also turned to thisposition. The selector arm is then placed upon step b of the second bar,the condenser rotated to the next most clockwise station and the volumeadjusted as before. These steps are repeated for the adjustment of thethird station. After the third station has been adjusted, the clampingnut I24 is tightened sufiiciently to hold all of the members I22 intheir adjusted positions when operating to restrain the condenseragainst rotation by spring 3. Cam I68 is turned to the position shown inFigure IX so as not to interfere with the motion of the lever I14. Selector arm I2I is placed upon step d of a selector bar and the manualcontrol pinion 56 disengaged from the train I6I. This allows thecondenser to rotate freely to the right and turn off the set.

The inverse order of procedure in setting the stops as disclosed aboveis necessary with this modification since, if all the stops were rotatedas a group, adjustment of the volume for the first station wouldposition all of the stop members in a radial direction and the camsurfaces I 65 would not be low enough to cut down the volume of asubsequent station of higher power than the station being positioned.

To set up a preselected sequence of stations to begin at a future time,one selector bar I3I for each 15 minute period of elapsed time, saveone, is set up in a clockwise direction with step d in position tocooperate with the tip of the selector arm I 2|. The bar representingthe last period of elapsed time is set with any other step in position.The desired sequence of stations then set up consecutively in aclockwise direction, bars I 3| presenting steps a, b, or c in accordancewith the station desired. To terminate the sequence, all subsequent barsare adjusted to present step d.

Rider 31, making one revolution each 15 minutes, engages the lever I42once each revolution and causes the pawl I43 to force the selector armI2I forward and step it one step (to the next bar I3I). If the arm I2Irests upon step d of this bar, bellcrank I5I holds detent 38 out of thepath of rider 31 and the rider 31 follows the gear 34 at a uniformrotational speed. If the arm rests on step a, b, or c, detent 38 isdropped into the path of the rider 31 and restrains it, causing therotation of gear 34 to store energy in the spring 36. As in the formermodification, when gear 36 has rotated almost a complete revolution,rider 31 is released from the detent 38, engages the stop 41 of the gear46 and, acting through gear I10 and pinion I69, rotates the condenser toits extreme counterclockwise position. Just prior to the point at whichrider 31 releases the condenser, it actuates the lever I42, stepping theselector arm to the next selector bar. After release from rider 31, thecondenser rotates slowly in a clockwise direction under the control ofthe governor I1I until the stop I25 corresponding to the selected stepof bar I3I is intercepted by the stop I62. This causes the condenser totune in the desired station, and the positioning of the shield I13 bythe cooperation of cam surface I65 and the follower I66 causes thestation to be received with the desired volume.

The selector arm I2I now being upon say step a, the detent 38 will belowered into the path of the rider 31 and when the rider reaches thispoint it will be restrained and the spring again tensioned as before.The above operations continue until the selector arm reaches the arrayof bars I3I which are set at step d, at which time the condenser whenreleased from the rider 31 will rotate to the extreme clockwise positionand cut off the set. The detent will be lifted from the path of therider 31 and the latter will rotate with the gear 34. It will be notedthat during the idle period, i. e., when the set is adjusted for manualoperation or when the selector arm is upon step d, the motor 33 is nottensioning the spring 36 and is merely idling at synchronous speed,thereby having a minimum of current consumption during this period.

Whenever the gear I06 is rotated through the medium of pinion I69, orwhenever it drives the governor I1I therethrough, the reaction upon thestub shaft of the pinion I69 will force the lever I16 in acounterclockwise direction. This will force the shield I13 upward,silencing the set, and will force the cam follower I66 downward, keepingit clear of the cams I65. When manually rotated through the train I6I,this does not necessarily occur, as the speed of manual rotation may notbe sufficient to actuate the governor I1I. The cam surfaces I65 havesufficient pitch to cause the follower I66 to ride thereover even whenthey are in the lowest position, so that when the condenser is manuallyrotated the lever will oscillate without hanging and moving the stopsout of adjustment.

The purpose of the volume control features above disclosed inconjunction with the automatic tuning arrangement is not to supplant butto supplement the conventional manual volume control by causing theinput to the set to assume a substantially constant level. The desiredlevel of reception can be adjusted to suit the occasion manually andwill be substantially the same for all stations upon the selected list.The cooperation between the automatic and the manual volume controlmeans is best shown by means of a simple circuit diagram such as thatshown in Figure XV. The shielding cylinder I13 is interposed between theprimary I60 and the secondary I59 of the antenna coupler, as abovedisclosed in connection with Figure IX, to control the input to the set.The output from the conventional radio frequency amplifier is rectifiedby a conventional diode rectifier and the rectified currents passthrough the manual volume control potentiometer I15, which controls theinput signal voltage of the first stage of audio frequencyamplification. The circuit also shows the connection of the power supplyswitch 60 and the manner in which it cuts off the set when engaged bypin I0 which is attached to the gear 6 or I06.

Also it may be desirable to include conventional automatic volumecontrol to compensate for va riations in the signal intensity of thesame station at various times and also to compensate for slightdiscrepancies in the operating action of the automatic input signaladjusting means herein disclosed. Especially would this be desirable inconjunction with the first modification, since with the high gear rationecessary to effect adjustment for each station, a slight inaccuracy orplay in the gears might change the signal level to some extent.

Various modifications of each of the devices may obviously be made bythose skilled in the art. For example, the specific number of stops 25or I25, the number of selector buttons 3| or selector bars I3I, or thenumber of teeth in the ratchet wheel 49 may be modified to suit desiredconditions of operation. When a different number of stops is used, it isobvious that the number of sectors a, b, c, d on the buttons 3i or stepsa, b, c, d on bars I3I must be equal to the number of stops plus one.Either modification may be designed to employ either buttons ill or barsI3I as their functions are identical, the tip of the selector arm beingdesigned to cooperate therewith.

()ther governing means may be provided for the rider in lieu of theself-governing spring 36. For example a gear of greater radius than therider which meshes with a pinion connected to a conventional governingmechanism such as I1I may be substituted for the leg 231 of the rider31. A stop would be provided upon its rear side to cooperate with thestop 41 when the rider is shifted axially as above described. The pinionshould be long enough so that the gear will mesh therewith regardless ofthe axial position of the rider.

The foregoing are a few modifications which will occur to those skilledin the art and other similar modifications may obviously be made withoutdeparting from the scope of my invention which I do not intend to belimited by the specific structures disclosed but only by the scope ofthe appended claims.

I claim:

1. In a radio receiving set, the combination of a tuning device, aspring for rotating the tuning device, means. for restraining the tuningdevice at any one of a plurality of positions corresponding to thefrequencies of desired stations, a plurality of adjustable selectorelements and means cooperating therewith in sequence for controlling therestraining means and determining the sequence in which the stations areselected, a synchronous motor for tensioning the spring, meansresponsive to the rotation of the motor for de-- laying the initiationof the sequence a predetermined time interval, means responsive to theinitiation of the sequence for energizing the radio set, means alsoresponsive to the rotation of the motor for determining the timeinterval between the selections of succeeding stations of the sequence,and means responsive to the termination of the sequence for deenergizingthe radio set.

2. The combination of a variable condenser having a rotary shaft, a stopcarried by the shaft, a stationary panel through which the shaftprojects, a substantially circular array of adjustable selector elementscarried by the panel, a selector arm rotatable about the shaft andadapted to engage the selector elements, means for rotating thecondenser shaft at predetermined intervals and for concurrently rotatingthe selector arm to the succeeding selector element, and a second stopmechanically controlled by the selector arm and positionable thereby inresponse to a particular adjustment of the selector element for engagingthe first stop and restraining the condenser shaft.

3. The combination of a variable condenser having a rotary shaft,arresting means carried by the shaft, a stationary panel through whichthe shaft projects, a substantially circular array of adjustableselector elements carried by the panel, a selector arm rotatable aboutthe shaft and adapted to engage the selector elements, means forrotating the condenser shaft at predetermined intervals and forconcurrently rotating the selector arm to the succeeding selectorelement, and a second arresting means mechanically connected to theselector arm and movable thereby to various positions in a directionparallel to the condenser shaft in accordance with the adjustment of theselector element for engaging the first arresting means and restrainingthe condenser shaft.

4. The combination as in claim 3, in which the first arresting meanscomprises a plurality of individually adjustable stops having variouspaths of travel, whereby they may selectively cooperate with the secondarresting means and restrain the condenser in any one of a plurality ofpositions in accordance with the adjustment of the engaged selectorelement.

5. The combination as in claim 3, in which the second arresting meanscomprises a plurality of individually adjustable stops which interceptvarious parts of the path of travel of the first arresting means,whereby they may cooperate therewith selectively an-d restrain thecondenser at any one of a plurality of positions in accordance with theadjustment of the engaged selector element.

6. An automatic tuning device for radio receivers comprising a tuningcondenser having a shaft, a panel through which the shaft projects, acircular array of adjustable selector elements upon the panelsubstantially concentric with the shaft, a selector arm rotatable aboutthe shaft for selectively engaging the elements, means responsive tooppositely directed axial movements of the arm for locking the armagainst rotation during engagement with an element and for unlocking thearm to permit rotation, and means for periodically disengaging the armfrom the engaged element and causing it to engage a succeeding element.

'7. The combination as in claim 6, in which the selector arm has apointed tip and in which each of the selector elements consists of abutton having a plurality of discrete sectors of varying thickness andis manually rotatable to present any one of the sectors to the tip ofthe selector arm.

8. The combination as in claim 6, in which each of the selector elementsconsists of a radially adjustable bar having a plurality of steps ofvarying thicknesses, and in which the locking means consists of a pairof cam surfaces upon the tip of the selector arm and in cooperativerelation to the bars.

9. A stop assembly for an automatic station selector comprising abushing having a longitudinally grooved body portion, a raised shoulderat one end of the body, a plurality of rotatably adjustable stop membersand interposed washers disposed upon the body, the washers having titsto engage the grooves in the body and prevent rotation of the washers,means disposed upon the other end of the body to clamp the members andwashers against the shoulder, a shaft passing through the bushing androtatable therein coaxiall'y with the stop' members, and a stop fixed tothe shaft and adapted to cooperate with the first stop members.

10. A stop assembly for an automatic station selector comprising abushing having a longitudinally grooved body portion, a raised shoulderat one end of the body, a plurality of stop members and interposedwashers disposed upon the body, the stop members having oval eyestherein to permit of radial and rotary adjustment of the members aboutthe body and the washers having tits to engage the grooves in the bodyand prevent rotation of the washers, and means disposed upon the otherend of the body to clamp the members and washers against the shoulder.

11. In a radio receiving set, the combination of a tuning device, a stopassembly for the device comprising a plurality of mechanicallyadjustable steps, a series of mechanically adjustable selector elements,means for engaging the elements in sequence and for selecting one of thestops mechanically in accordance with the adjustment of the engagedelement, means for rotating the tuning device at predeterminedintervals, and means responsive to the adjustment of the selected stopfor controlling the tuning of the device and the level of reception ofthe tuned signals.

12. In a radio receiving set, the combination of a tuning device, a stopassembly for the tuning device comprising a plurality of radially androtatably adjustable stops, a series of adjustable selector elements,means for engaging the elements in sequence and for selecting one of thestops in accordance with the adjustment of the engaged element, meansfor rotating the tuning device at predetermined intervals, meansresponsive to the rotary adjustment of the selected stop for controllingthe tuning of the device, and means responsive to the radial adjustmentof the selected stop for controlling the level of reception of the tunedsignals.

13. In a radio receiving set, the combination of a tuning device, a stopassembly for the device comprising a plurality of mechanicallyadjustable stops, a series of mechanically adjustable selector elements,means for engaging the elements in sequence and for selecting one of thestops mechanically in accordance with the adjustment of the engagedelement, means for rotating the device at predetermined intervals, meansfor preventing the production of signals during rotation of the device,and means responsive to the adjustment of the selected stop forcontrolling the tuning of the device and the level of the receivedsignals.

14. In a radio receiving set having a rotatable tuning device, means forsilencing the set during the rotation of the device comprising a gearcarried by the device, a pinion meshing with the gear, a pivoted leverupon which the pinion is mounted for rotation, and a silencing deviceactuated by oscillation of the lever in response to the reaction of thepinion upon the lever.

15. In a radio receiving set, the combination of a high frequencytransformer having a primary and a secondary winding, a rotatable tuningdevice, a plurality of cams carried by the tuning device, a cam followeradapted to cooperate with the cams, an electrically conducting shieldmovable to various positions between the windings and means controlledby the cam follower for varying the position of the shield between thewindings in accordance with the ad- Justments of the cams.

16. In a radio receiving set having signal responsive circuits and arotatable tuning device, means for silencing the set during rotation ofthe device and for controlling the level of the tuned signals comprisinga rotatable shaft, a radially displaceable member attached at one end tothe shaft, a metallic cylinder and an annular resistor concentric withthe shaft and having the other end of the contact member therebetweenwhereby the member contacts the cylinder when in rotation and theresistor when at rest, electrical connections from the cylinder,resistor, and contact member to the signal responsive circuits, andmeans for rotating the shaft from the tuning device.

17. Means for effecting intermittent rotary oscillation of a radiotuning device comprising a rotatable driven member connected to thedevice, a rotatable intermediate member, and a continuously rotatabledriving member, a spring connected between the intermediate member andthe driving member, means for restraining the intermediate member andcausing the spring to be tensioned by the rotation of the drivingmember, means responsive to the rotation of the driving member formoving the intermediate member in an axial direction, releasing it fromthe restraining means and causing it to engage the driven member,whereby both may be rotated by the spring, means responsive to therotation of the intermediate member for causing it to release the drivenmember, and means for rotating the driven member in the reversedirection upon release by the intermediate member.

18. Means for producing intermittent rotation of a radio tunercomprising a synchronous mo tor, a gear driven by the motor, a rider anda driven member in substantially coaxial alignment with the gear, adetent for the rider, 2. spring connected between the gear and rider andadapted to be tensioned by the gear when the rider is restrained by thedetent, means responsive to the rotation of the gear for causing therider to escape the detent and to engage the driven member, therebyrotating the latter under the influence of the spring, means responsiveto the rotation of the rider for causing it to disengage the drivenmember, a cam follower for controlling the detent, a cam cooperatingwith the follower, a pawl and ratchet wheel for rotating the cam, meansfor causing the rider to actuate the pawl, and means for causing thefollower to follow the gear when the detent is disabled by thecooperation of the cam and follower.

EDWARD W. ALLEN, J R.

